RAIL bosses faced further embarrassment last night after the discovery of another fault on a multi-million pound fleet of trains operating in North Wales.

First North Western's (FNW) brand-new Class 175 Coradia trains have already suffered brake problems and were unable to cope with hot weather last summer.

Now the doors are causing problems. More than half of the fleet, which runs on the North Wales coast line, is out of action as modifications to brakes and doors are carried out.

When two of the modified trains were used together for the first time it caused what FNW sources described as a "fiasco".

An insider told the Daily Post two modified trains were connected together at Birmingham's New Street station on Monday to create a sixcarriage train to go to Holyhead.

He said: "The train was delayed for nearly two hours at Birmingham New Street after the driver was unable to release the brakes.

"They were jammed solid because the train's computer thought the doors were still open. The fault had not shown up before, this was the first time two units with modified door control circuits had operated together."

The train was eventually divided, and one three-carriage unit operated the service to Holyhead, causing crowding and inconvenience.

Meanwhile spare staff were " scrambled" to remove the other train and try to fill in gaps caused by the delays.

Similar problems have occurred at Chester, also causing delays and inconvenience to travellers.

The insider said: "A Coradia unit suffered technical problems which meant other trains had to operate services on the North Wales line while the faulty unit was taken to Manchester for rectification."

The company is being hampered by the withdrawal of three of the brandnew trains for repairs after suffering damage in the recent storms.

An FNW spokesman said the situation was being investigated by engineers and apologised for the delays.

He said: "No trains have been cancelled but the shortage of trains has meant some services have suffered delays."

FNW has suffered a string of problems with the 100mph trains. All 27 should have been in service by May last year. All the trains have been built but only 23 have been accepted into service.

Three are still being tested and one is in the South of England being modified. The company bought the trains believing they would run for 70,000 miles without failure. However, they are believed to be achieving 7,000 miles per train.

Last year the fleet was taken out of service while brake problems were investigated. At one stage the trains were also affected by hot weather.